It is widely recognized that flue gases often contain heat and water. It is known to extract water from flue gas in water-constrained environments, for example, in the context of a desert-situated fossil-fuel-fired power plant. It is also known to extract heat from flue gas, for example, to pre-heat boiler feed make-up water. However, often only relatively modest amounts of heat can be extracted from flue gases using conventional technologies; if excess heat is extracted, condensation can occur, leading in many applications to the possibility of undesirable corrosion. As well, because of the relatively wide availability of water in areas where flue gases are likely to be found, i.e. inhabited areas, the recovery of water from flue gas using known processes is rarely economic.